Great Mills, MD Water Safety: 55/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
If you're checking Great Mills, MD tap water safety, the short answer is: average — violations are present in parts of the city and specifics depend on which water system serves your address.
How Great Mills Compares
Data: EPA SDWIS Last verified: 2026-06-03
Great Mills Water: The Quick Version
- Homes built before 1986: 22% — older plumbing may contain lead solder.
- Estimated remediation: $1,600 per household.
- CDC health risk index: 12.51 — above typical levels.
Water Systems Serving Great Mills
Great Mills, MD is covered by 2 major water utilities out of 2 federally tracked systems, each managing its own pipes, treatment processes, and EPA filings. What a household gets from the tap depends on which provider's system serves that address.
Overview
We track water quality and home safety data for 1 ZIP code in Great Mills, Maryland (population ~6,976), covering 2 community water systems serving approximately 43,922 people region-wide.
No EPA violations recorded across any ZIP codes in Great Mills — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Great Mills: C (55/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Great Mills water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Great Mills
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 20634 | C | LORD CALVERT TRAILER PARK | 892 |
All ZIP Codes in Great Mills
- 20634 [C]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
CDC Health Data for Great Mills
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
How Old Is Great Mills's Housing Stock?
Housing age data helps assess potential lead pipe and infrastructure risks. Newer housing stock generally means lower plumbing-related contamination risk.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Although a small portion of Great Mills's homes predate 1986, the median build year of 1994 indicates the majority of the city's residential plumbing was installed after lead solder was banned — which tends to reduce the plumbing-related component of lead exposure at the household level.
Most homes in Great Mills were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Great Mills: Remediation Cost in Perspective
In Great Mills, property wealth outpaces what documented remediation typically demands — the equity burden lands well within the low tier.
Remediation costs in Great Mills are relatively low compared to home values. The $800–$2,600 estimated range is a small fraction of median property value. Home values are 22% below the Maryland average.
Protecting Children from Lead in Great Mills
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Whenever aggregate samples pass the federal action benchmark and pre-rule housing — 22% in Great Mills — represents a smaller fraction, lead occupies a lower priority on the local picture.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Great Mills
The National Flood Insurance Program captures decades of claims at the local level, building a record of cumulative community flood exposure. For Great Mills, that record documents 30 claims and 100% of ZIP codes inside FEMA-designated flood zones. What makes those numbers relevant to water quality is the set of mechanisms flooding activates: heavy precipitation that floods treatment intake zones can introduce contaminants upstream of normal filtration; well casings in low-lying areas can be infiltrated by floodwaters carrying bacteria, sediment, and chemical residue; and distribution system pressure changes during flooding can create backflow conditions. These effects become more probable as flood frequency and magnitude increase — and the NFIP record indicates both are meaningful factors locally.
Great Mills has a moderate flood history with 30 FEMA claims averaging $18,833 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,600</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Great Mills
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
Deep Dive Reports
Detailed analysis for Great Mills, MD